diff options
author | Will Deacon <will@kernel.org> | 2022-12-06 14:01:49 +0300 |
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committer | Will Deacon <will@kernel.org> | 2022-12-06 14:01:49 +0300 |
commit | f6ffa4c8c177c0b52d1c849289b08178f6da0eea (patch) | |
tree | 299791f71bfb2a9e9312e59ebcc8d4b157f8b5bc /arch/arm64/include | |
parent | 9f930478c648d25e3a4c3db3d69a65cf05ff939a (diff) | |
parent | 3b619e22c4601b444ed2d6a5458271f72625ac89 (diff) | |
download | linux-f6ffa4c8c177c0b52d1c849289b08178f6da0eea.tar.xz |
Merge branch 'for-next/dynamic-scs' into for-next/core
* for-next/dynamic-scs:
arm64: implement dynamic shadow call stack for Clang
scs: add support for dynamic shadow call stacks
arm64: unwind: add asynchronous unwind tables to kernel and modules
Diffstat (limited to 'arch/arm64/include')
-rw-r--r-- | arch/arm64/include/asm/module.lds.h | 8 | ||||
-rw-r--r-- | arch/arm64/include/asm/scs.h | 49 |
2 files changed, 57 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/module.lds.h b/arch/arm64/include/asm/module.lds.h index 094701ec5500..dbba4b7559aa 100644 --- a/arch/arm64/include/asm/module.lds.h +++ b/arch/arm64/include/asm/module.lds.h @@ -17,4 +17,12 @@ SECTIONS { */ .text.hot : { *(.text.hot) } #endif + +#ifdef CONFIG_UNWIND_TABLES + /* + * Currently, we only use unwind info at module load time, so we can + * put it into the .init allocation. + */ + .init.eh_frame : { *(.eh_frame) } +#endif } diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h index 8297bccf0784..ff7da1268a52 100644 --- a/arch/arm64/include/asm/scs.h +++ b/arch/arm64/include/asm/scs.h @@ -5,6 +5,7 @@ #ifdef __ASSEMBLY__ #include <asm/asm-offsets.h> +#include <asm/sysreg.h> #ifdef CONFIG_SHADOW_CALL_STACK scs_sp .req x18 @@ -24,6 +25,54 @@ .endm #endif /* CONFIG_SHADOW_CALL_STACK */ + +#else + +#include <linux/scs.h> +#include <asm/cpufeature.h> + +#ifdef CONFIG_UNWIND_PATCH_PAC_INTO_SCS +static inline bool should_patch_pac_into_scs(void) +{ + u64 reg; + + /* + * We only enable the shadow call stack dynamically if we are running + * on a system that does not implement PAC or BTI. PAC and SCS provide + * roughly the same level of protection, and BTI relies on the PACIASP + * instructions serving as landing pads, preventing us from patching + * those instructions into something else. + */ + reg = read_sysreg_s(SYS_ID_AA64ISAR1_EL1); + if (SYS_FIELD_GET(ID_AA64ISAR1_EL1, APA, reg) | + SYS_FIELD_GET(ID_AA64ISAR1_EL1, API, reg)) + return false; + + reg = read_sysreg_s(SYS_ID_AA64ISAR2_EL1); + if (SYS_FIELD_GET(ID_AA64ISAR2_EL1, APA3, reg)) + return false; + + if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) { + reg = read_sysreg_s(SYS_ID_AA64PFR1_EL1); + if (reg & (0xf << ID_AA64PFR1_EL1_BT_SHIFT)) + return false; + } + return true; +} + +static inline void dynamic_scs_init(void) +{ + if (should_patch_pac_into_scs()) { + pr_info("Enabling dynamic shadow call stack\n"); + static_branch_enable(&dynamic_scs_enabled); + } +} +#else +static inline void dynamic_scs_init(void) {} +#endif + +int scs_patch(const u8 eh_frame[], int size); + #endif /* __ASSEMBLY __ */ #endif /* _ASM_SCS_H */ |